Valve testing apparatus



Oct. 7, 1941, R. sHEPPARD VALVE TESTING APPARATUS Filed July 8, 1958 Inventor* t Raymond Sheppard,

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is Attorney Patented Oct. 7, `1941 VALVE TESTING APPARATUS `Raymond Sheppard, Niskayuna, N. Y., assgnor to General Electric Company, a corporation ofi,

New York Application July 8, 1938, Serial No. 218,247

(Cl. 'i3-51) 6 Claims.

The `present invention relatesto valve testing arrangements for testing'the free movability of servo motor operated valves such as emergency stop valves used in conjunction with elastic uid turbines and provided in the inlet conduit i thereof ahead of thecontrol valves as regards the flow of elasticiiuid therethrough. These emergency 'stop valves are provided to effect quick stopping of the flow of elastic fluid to the turbine or other consumer in case of emergency. Beingoperated only in emergency cases they may remain in one position, that is, in full opening position for a long time during which foreign matter contained in the elastic iuid may enter the packing sleeves for the stemY or the packing sleevesand the stem may corrode, preventing free movement of the valve stem, should emergency call for closing the valve. Thereforeit is desirable to test the valve from time to time to make sure that its free movability isnot impaired. During the testing it is sufficient `to move the valve slightly up and down without closing it. In fact, closing is most undesirable during thetesting as it would completely interrupt the flow of elastic iluid through the valve and as it might take considerable time to reopen the valve once. itis shut. This is true particularly with regard to unbalanced single disk emergency stop valves held. in position by a small air pressure operated servo motor. In such a case, closing of thefstop valve would necessitate subsequent closing of` the control valve to balance the pressure across the Vstop valve and thereby to make it possible `to. reopen thelatterby means of the comparativelysmall servo` motor. Y Q The object of my invention is to provide a valve testing arrangement whereby a valve, such asl an emergency stop valve, may be readily tested as regards its free movability during operation without ever causing complete closing of the valve.` This is accomplished by my invention by the provision `of a bypass connected with the opposite sides of the piston in the servo motor and including a test valve which upon actuation permits displacement of a limited amount of fluid in the servo motor. The test valve is preferably biased into non-operativeposition `so that upon actuation it returns automatically to such position.

For a better understanding of what I believe to be novel rand my invention, attention is directed to the following description and the claims appended thereto in connection with the accompanying drawing. K Y d The single figure of the drawing illustrates somewhat diagrammatically a valve testing arrangement in accordance with my invention.

` The arrangement comprises an emergency stop valve having a casing I 0 with an inlet I'I for con'- nection to a source of elastic fluid and an outletV I2 for connection to a consumer. In the case of an elastic fluid turbine the outlet I2 is connested to a turbine valve chest containing control valves, not shown. A movable valve member I3 with afstem I4 is disposed in the casing II) with the member I3 in cooperative relation with a valve seat I5. The stem I4 projects througha packing or sealing I6 and has a lower end con-' nected to a piston I I movably disposed in a cylinder I8 and biased in downward direction by a compression spring I9. `The piston with the cylinder forms aservo motor. Operating fluid, inthe present instance air under pressure, isconducted-to the lower portion of the cylinder I3 by aconduit 20 which is connected to a reversing valve 2li. The latter lincludes two movable valve members 22 and 23 secured to a stem 24. Ordinarilythe valve 22 is inopening and the valve 23 in closing position. Air under pressure .is supplied from a source throughia conduit 25 past the valve 22 through the conduit 20 to the lower end of the servo motor cylinder I8. Upon re.- versal of the positions of the valves 22 and 23 the valve 22 disconnects the conduit 2U from the source of supply and the valve 23 connects the conduit `2III to a discharge conduit 2S, permitting draining of iiuid from the lower part ofthe cylinder I8 and thereby causing downward move- A' ment yof the piston Il and closing of the emergency stop valve I3. 4The stem 24 for thevalves 22 and 23 is held in the normal position by means of a latch 2l which has a finger 28 in'cooperative relation with an emergency governor 29 secured to a shaft 33. The latter may be a shaft of the turbine to be controlled. During emergency condition the emergency governor causes turning of the ringer 28 whereby the latch 21 is removed from the stem 24, permitting upward movement of the latter into reversing position by the action of a compression spring 3I.

In order to .test the emergencystop valve, I provide means causing limited movement of the emergency stop valve without permitting it to move into closing position. This means includes a test valve 32 which has a cylinder 33 with ports 34, 35, 36 and a movable valve member 31. The valve member 3l has two valve heads 38 and 39 arranged so thatthe head 38 normally covers the port 35 while the space,r 40 formed between the heads permits communication of the ports 34 and 36. The port 34 is connected by a conduit 4I to the cylinder I8 above the piston I1 and the port 35 is connected by a conduit 42 to the cylinder I8 below the piston I1 so that normally the test valve permits discharge of fluid from the space above the piston I1 through the conduit 4I and the test valve port 36 which may be connected to atmosphere in the case of an air pressure operated servo motor. The movable valve member of the test valve is normally held in the position shown by means including a collar 43 fastened to the movable member of the test valve and biased towards a shoulder formed on the casing 33 by a compression spring 44.,

During testing the movable valve member has to be moved upward. To thisend it is connected to a hand lever 45 supported by a fulcrum 46 on the casing 33 and biased downward, that is, into normal position of the valve by a tension spring 41. Upon upward movement of the movable valve'member 31 by actuation of the hand lever 45 the lower valve head 39 rst covers the port 36, preventing further discharge of fluid from the upper side of the piston I1 intheY servo motor cylinder I8 and thereafter the upper valve head 38 uncovers the port 35 and thereby establishes communication between the conduits 4I and 42. The latter then form a bypass with regard tothe upper and lower side of the piston I1 in the cylinder I8, causing displacement of fluid under pressure from the lower side to the upper side. As pressure builds up on the upper side of the piston I1, the latter is forced downward. 'Ihis movement continues until the piston I1 covers the port connection with the conduit 42 and stops further displacement of fluid between the upper and lower sideof the piston and consequently prevents movement of the piston I1 into its lower end'position in which the valve I3 would be shut. Upon actuation of the test valve by upward turning movement of the lever 45 the latter returns to its normal position by action of the springs 44 and 41. Thus, during testing of the valve I3, all that is necessarynis to moveV the Vlever up and down a few times and see whether the emergency stop valve I3 moves freely. Movement of the valve I3 with its stem I4 during the testing operation is indicated by a signal lamp 48 forming part of an electric circuit 48 which includes contacts 58 and a contactmaking member 5I secured to the stem I4. The circuit is normally open. Upon downward movement of the stem I4 the contact-making member-5I closes the contacts 50, whereupon the lamp 48 lights` up, thus indicating movement of the stem I4.

Thus, Vwith my invention I have accomplished an improved construction and arrangement for testingY the operating condition of a hydraulic motor operated machine element such as a stop valve. Such hydraulic motor according to my invention has a pressure chamber with a rst port through which operating iluid is displaced during normal operation and in addition another port between such first port and the normal operating position of the motor piston, which other port is connected to a valved conduit and upon actuation of the valvepermits a limited displacement of operating fluid in the hydraulic motor.

Having described the method of operation of my invention, together with the apparatus whichA I now consider to represent the best embodiment thereof, I desire to have it understood that the apparatus shown is only illustrative and that the invention may be carried out by other means.

While I have described my invention as a valve testing arrangement, I desire to have it understood that it is not necessarily limited thereto and may be applied generally to the testing of the movability of machine elements having stems subject to sticking during operation, for example, in testing the operability of an emergency brake, an emergency door opener, a railroad cross-gate operator, etc.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. The combination with a valve having a stem and a fluid-pressure operated servo motor having a piston connected to the stem, of means connected to the servo motor for testing the movability of the stem without causing complete closing of the valve, said means comprising a valved bypass connectedto the motor on oppositesides of the piston for effecting a limited variation of fluid pressure in the servo motor.

2. Valve testing arrangement for a valve having a stem and a iluid pressure operated servo motor having a piston connected to the stem,

comprising a bypass with a valve connected to the servo motor on opposite sides of the piston to check the movability of thestem, said bypass being automatically rendered ineffective in response to a limited movement of the stem.

3. Valve testing arrangement for a valve having a stem and a iluid pressure operated servo motor with a piston connected to the stem normally to hold the valve in openposition, said arrangement including means for testing the movability of the stem without permitting the valve to be moved into closing position, said means comprising a bypass connected to the servo motor on opposite sides of the piston, a test valve in the bypass-including means normally biasing the test valve into closing position, one end of the bypass beingv connected vto the servo motor near the piston whereby a limited movement of the piston interrupts the flow of fluid through the bypass and renders it ineffective. y

4. The combination with an emergency stop valve having a stem, a cylinder having a piston connected to the stem, a spring engaging the piston and means for supplying air under pressure to the cylinder normally to hold the valve in open position, of means for checking the movability of the valve stem without permitting closing of the valve, said means comprising a bypass connected tothe cylinder on opposite sides of the piston and a valve having two heads connected in the bypass with one head normally closing the bypass and the space between the heads connecting one side of the piston with the atmosphere.

5. In a testing apparatus the combination with a fluid pressure casing having an opening, a stem slidably projecting through the opening and having sealing contact therewith, and a hydraulic motor for moving the stem, said motor having a casing and a piston connected to the stem and normally held in a xed position, of means for effecting limited movement of the 'piston from its normal operating position finto an intermediate position to test the movability of said stem, said means comprising a valved bypass connected to the casing on opposite sides of the piston, one end of the bypass being connected to a point of the hydraulic motor in proximity of the normal operating position of the piston to permit the discharge of only a limited amount of operating fluid from the motor.

6. In a testing apparatus the combination with a machine element having a casing with an opening, a stem having sliding t in the opening, and a hydraulic motor including a casing forming a pressure chamber with a port and a piston. movably disposed in the casing and oonnected to the stem, of means for effecting limited 10 movement only of the piston from its normal position into an intermediate position to test the operating condition of the machine element, said means comprising a vaived by-pass connected to the casing on opposite sides of the piston with one end of the bypass connected to a point of the casing between the port and the normal operating position of the piston.

RAYMOND SHEPPARD. 

